Loosing fish dont know why
 

I have a 200 gal reef tank that has been running for 3 months . Water conditions are perfect . Have not lost a single SPS LPS or soft coral since day one but keep loosing fish :cry:. I currently have a yellow tank , sailfin 3 clowns and 3 bi color dotty backs .

Any small fish IE Cardinals any wrasses, new clowns seem to last up to 2 weeks and then mysteriously go missing . No signs of the fish just simply gone . I thought at first the dottys were killing them off :twised:but they never show any signs of any aggression with during the day or at nite .

It was suggested that I may have crabs ( not hermits ) that came in the live rock that might attacking at a weak moment at nite when the fish are searching around . I have spotted a few 2-3 crabs about the size of a nickle that come out at nite and eat algae .

Any thougths:question:

Post your specific water parameters, and maybe we can start there. Do you QT your fish? How quickly did you add all your fish? Was your tank set up from a previously existing system?

Can you list the fish that have died? In what order too if you can remember.

CA 420 , mg 1320 , no3 no2 near zero . phos near 0 . Ph 8.2 Kh 9
temp stable at 77-78 f weekly 5% water changes .
185 gal tank 165 gal suno with refugium .
System set up form scratch 3.5 months ago
200 lbs live rock. shallow live sand bed with more live sand in refuge
Skimme rin sump ( euro 250) ca reactor , carbon 1 lb changed monthly in ractor tube .Hammer head pump for sump and dart with oceans motions recirc valve for recric and current within the tank total volume change near 8000 gal per hour . # 250 watt dohble end MH lights with 2 5 ft 80 watt vho for color . photo period 8 hours

Fish are kept in refug for 2 weeks . Added several fish at once to avoid any selectivity form aggressive species.
Lost 3 clowns on 2 separate occasions over 3 week period . Added 3 cardinals and a yellow wrasse at one time .They seemed compatible in the sump and did well for 3 weeks then slowly the cardinals would go missing one at a time over a period of 2 weeks . The wrasse I did not see after the 2nd day.

I would doubt it was water quality as all of sps etc are very healthy and growing.

Nothing in your set up description sounds off, or the cause.

What about the SG of your system?

Was your rock dry or live when you put it into your system? Are all these fish from the same source? Right now I'm thinking; another unknown pred. you haven't seen yet, possibly infection/disease, or even residual cyanide effects that are just unfortunately hitting you all at once.

Spec gravity is 1.025 . I cant figure it out either . Not all of the fish are bought from same store. My last addition was a yellow tang which is doing great 3 weeks strong eating well etc . What do you think of the crab idea .. ?? B.s or any validity . Do you think the dotty backs could be that aggressive when the lights go out . I dont see any aggression during the day

I'm leaning towards a larger crab. Something you haven't seen yet. I'm thinking probably at least 2-3". Doubtful its the dottybacks if you aren't seeing any of this behavior when the lights are on. Since they are all from different sources, they have to be sharing something to make the virus/infection angel plausible, which doesn't seem so.

Sorry to hear of your losses.

1) Your water parameters look good but just because your corals thrive it does not mean it is a healthy environment for fish. But your readings do indicate the acceptance for fish. Also they survived well in the same water for 3 weeks but in a different tank.

2) Losing 10 fish over a 3 week period ( if I am correct) could mean a few predators and an efficient clean up crew.

3) Could you list what inhabitants you have and what you have lost and when?

4) At what time during the 3.5 months were the first fish added and inverts added etc.

Here is a few known points and a few questions. I have a feeling it is a mantis or a few bad crabs. Keep us posted and consider a trap in the meantime.

Good Luck
Kevin

I think my best option at this point since I am not going to change the water conditions is to set a trap and see what I catch :twised:

Ill keep you posted

You'd be suprised what you can find hiding in 200lbs of LR....even months and months later. It could be a larger crab or even a mantis.


You should try spotlighting a bit late at night with a flashlight, see if you can see anything funny.

I picked up a blue led flashlight that is ultrabright but does not seem to scare my tankt he way a white light does.
it works really well for having a look at my pistols and crabs at night, I caugt one crab that way.